The spread of AIDS through heterosexual contact has been dramatic in east-central Africa. In Rwanda, the prevalence of human immunodeficiency virus (HIV) infection in urban adults now exceeds 30% and is increasing at a rate of 3-5% per year in prenatal care clinics. Existing research projects coordinated by the National AIDS Control Program (NACP) and funded by the World Health Organization (WHO), the US National Institutes of Health (NIH), the Belgian government, and the European Economic Community have monitored HIV prevalence and incidence rates in several high risk groups in Kigali, the capital city. Infrastructures for recruitment and followup of research subjects have been established, and laboratory capacities include serology and PCR for HIV. All of these projects and facilities are located within 1 km of each other, and an excellent collaborative environment exists between the various groups. A recently renewed NIH grant to the University of California in San Francisco (UCSF) will provide funding for prospective study of the incidence and predictors of heterosexual transmission of HIV in over 600 discordant couples, a group known to maintain high seroincidence rates after intensive counselling. A liaison has been established between UCSF, field investigators in Rwanda, and the St Louis University AIDS vaccine Evaluation Unit (AVEU), an NIH funded program which has an established track record with vaccine trials and conducts ongoing Phase I/II studies of AIDS/HIV vaccines. The St Louis AVEU can contribute funds for training 3 Rwandan physicians in immunologic, virologic, and epidemiologic techniques used in AIDS/HIV vaccine trials. In preparation for immunogenicity and efficacy studies of AIDS/HIV vaccines in Rwanda, we propose to: 1. Develop videos for the general public that will address questions about AIDS/HIV vaccines and promote voluntary HIV testing and counselling for couples. 2. Establish a reference laboratory for the diagnosis of sexually transmitted diseases which may act as co-factors for HIV transmission, and train Rwandan health professionals in the appropriate clinical and laboratory skills. 3. Strengthen virology/immunology laboratory capacities with the addition of an on-site AVEU physician and with equipment to allow processing of samples for study of genetic and antigenic variants of HIV. 4. Train Rwandan physicians, nurses, pharmacists, laboratory technicians, and data programmers in the epidemiologic, clinical, and laboratory skills needed to carry out randomized control clinical trials of future AIDS/HIV vaccines. 5. As a demonstration project, carry out a randomized control trial of hepatitis B vaccine in HIV concordant negative/anti HBc discordant couples, allowing on-site personnel to refine their skills. An added advantage is that Rwanda has been selected by the WHO Global Program on AIDS as one of 4 countries uniquely suited to preventive and therapeutic trials of AIDS/HIV vaccines. WHO will ensure the coordination of government and international groups involved in future AIDS/HIV vaccine trials in Rwanda.